Dissolved Calcium and UV Water Treatment 1

[PEDARRIN2]

Was reading a resource, (

http://www.nesc.wvu.edu/pdf/dw/publications/ontap/2009_tb/ultraviolet_DWFSOM53.pdf)

and noticed it made a statement on page 3, "And some dissolved
minerals, such as calcium, have a tremendous negative effect on UV absorbance."

I realize that hard water can deposit scale on the interior surfaces of the apparatus which is not good, but I don't think that is what is being referenced. It almost sounds like the dissolved ions hinder the ability of the biological contaminants from absorbing the UV.

Does anybody have any experience with this or is this an uninformed statement made by a less than technically qualified source.

 

[bimr]

Overall, the articles from NESC.WVU.EDU are generally informative.

The article that you are quoting is from 2000 and perhaps a bit of an overstatement. There have been a number of studies since than that show dissolved calcium in the amounts present in potable is not a problem.

http://www.unh.edu/wttac/WTTAC_Water_Tech_Guide_Vol2/uv_water.html

Significant operating experience since the article was published has also helped to define the need for the frequency of cleaning due to scaling.

 

[PEDARRIN2]

bimr,

Thank you for the explanation.